EXAM 2 REVIEW
Chapter 14:
1. The figure represents an electron micrograph image observed after a mixture of a segment of a double stranded DNA from within a gene and the mature mRNA made from that gene was heated and slowly cooled. Which strand in the figure is DNA?
A. Strand A
B. Strand B
C. Both strand A and B
D. Neither strand A nor B
2. Which of the following correctly states a difference between poly(A) polymerase, which adds A nucleotides to pre-mRNAs during processing, and other RNA polymerases?
A. Poly(A) polymerase does not require a template strand in order to add ribonucleotides to the polymer
B. Poly(A) polymerase extends polymers in 5’ direction instead of in the 3’ direction
C. Poly(A) polymerase adds deoxyribonucleotides instead of ribonucleotides
D. Poly(A) polymerase requires the assistance of snRNAs in order to function
3. Which of the following events does NOT occur during pre-mRNA processing?
A. A 7-methylguanosine CAP structure is added to the 5’ end of the molecule
B. Intron sequences are removed
C. Exon sequences are joined together
D. Additional G residues are added to the 3’ end of the molecule

4. RNA function
A. What are some characteristics of introns?
B. What are the four types of pre-mRNA posttranscriptional modifications?
What are their purposes?
C. What are some characteristics of tRNA

Chapter 15
5. How many reading frames are theoretically possible in a mRNA molecule?
A. One
B. Two
C. Three
D. Six
6. There are __ different codons, which encode 20 amino acids and 3 stop codons.
A. 16
B. 20
C. 64
D. 61
7. An mRNA has the codon 5’ – UAC – 3’. What tRNA anticodon will bind to it?
A. 5’ – AUG – 3’
B. 5’ – GUA – 3’
C. 5’ – ATC – 3’
D. 5’ – CTA – 3’
8. How are amino acids linked to tRNAs?
A. The carboxyl group of the amino acid is covalently bound to the 3’ hydroxyl group of the tRNA
B. The amino group of the amino acid is covalently bound to the 3’ hydroxyl group of the tRNA
C. The carboxyl group of the amino acid is covalently bound to the 5’ phosphate group of the tRNA
D. The amino group of the amino acid is covalently bound to the 5’ phosphate group of the tRNA
9. Which of the following best describes an auxotrophic mutation?
A. Auxotrophic mutations prevent the function of tRNA synthetases
B. Auxotrophic mutations block the initiation of translation
C. Auxotrophic mutations cause a microorganism to fail to synthesize an essential metabolite
D. Auxotrophic mutations cause the loss of a particular tRNA

10. Protein structure and genetic code:
A. Demonstrate your understanding of the formation of a peptide bond
B. Describe the four levels of structure of a protein. What primarily determines the secondary and tertiary structures of a protein?
C. Through wobble, a single ______ can pair with more than one _____.

Chapter 2- Mitosis
11. Cells that are metabolically active but are not destined to proliferate are said to be in what phase of the cell cycle?
A. S phase
B. G0 phase
C. G1 phase
D. G2 phase
12. During which stage of the cell cycle are individuals not visible within cells?
A. Anaphase
B. S phase
C. Metaphase
D. Telophase
13. At which phase of the cell cycle would a cell normally check for the integrity of its DNA?
A. M phase
B. G1/S phase
C. G2/S phase
D. G1/S and G2/M phases

14. Mitosis:
A. What defines a diploid cell?
B. What would be the result of a chromosome did not have a kinetochore?
C. What are the main steps and checkpoints of the cell cycle?
D. What are the main steps and defining features of mitosis?

Chapter 2-Meiosis
15. Crossing over refers to
A. The random segregation of dyads in metaphase I of meiosis
B. The formation of lateral elements between paired homologs during zygonema
C. The onset of homology search in the leptonene stage of meiosis I
D. Genetic exchange between nonsister chromatids during meiosis.
16. Which of the following statements about homologous chromosomes is true?
A. Homologous chromosomes pair up and undergo recombination during prophase of mitosis
B. They contain all of the same genes but not necessarily the same alleles
C. In each cell, there are two pairs of homologous chromosomes-one pair from each parent
D. They ay are identical sequences of base pairs.
17. When do sister chromatids separate during meiosis?
A. Metaphase I
B. Metaphase II
C. Anaphase I
D. Anaphase II
18. In this figure, you can see that the ________ have just become aligned at the metaphase plate
A. Nonhomolgous chromosomes
B. Telomere pairs
C. Non-sister chromatids
D. Homologous chromosomes

19. Meiosis:
A. What are the steps and end products of meiosis?
B. When does crossing over take place? Why is it important?
C. What is an example of a reductional division? Equational division?
D. A cell in G1 of interphase has 12 chromosomes. How many chromosomes and how many DNA molecules will be found per cell when the original cell progresses to the following stages
Stage
G1 of interphase
G2 of interphase
Chromosomes
12
DNA molecules
Prophase of mitosis
Anaphase I of meiosis
Anaphase II of meiosis
Prophase II of meiosis
After cytokinesis in mitosis
After cytokinesis in meiosis

Chapter 3-Mendelian Principles
20. In a diploid organism, which two genotypes below, when either is present in an individual, would be expressed as the same phenotype?
A. Homozygous dominant and homozygous recessive
B. Homozygous dominant and heterozygous
C. Homozygous recessive and heterozygous
21. What ratio of offspring would be expected from a cross of individuals who are heterozygous for Mendel’s height and color traits? (Assuming tall is dominant to dwarf, and green is dominant to yellow)
A. 3 tall green: 1 dwarf short
B. 1 tall green: 1 tall yellow: 1 dwarf green: 1 dwarf yellow
C. All tall green plants d. 9 tall green: 3 tall yellow: 3 dwarf green: 1 dwarf yellow
22. On the basis of segregation and independent assortment, how many different types of gametes can be formed from an organisms that has a diploid number of 12?
A. 6
B. 12
C. 64
D. 4,096
23. If a home garden were planted with all hybrid round peas, what phenotypic proportions would be observe din the progeny? (The wrinkled trait is recessive)
A. 4/4 round
B. ¼ round and ¾ wrinkled
C. ½ round and ½ wrinkled
D. ¾ round and ¼ wrinkled
24. If a yellow pea plant with round seeds that has the genotype GgWw is crossed to itself, what proportion of the offspring will be green with round seeds?
A. 3/16
B. 9/16
C. 1/16
D. 0

25. Mendelian principles:
A. Describe a monohybrid cross. Make an example Punnett square or branch diagram
B. Describe a di-hybrid cross. Make an example Punnett square or branch diagram
C. What is the principle of segregation?
D. Describe the sum and product rules and when to use them
E. What is a test cross and when do we use one?

Chapter 4- Sex determination
26. You discover a new amphibian and name the sex chromosomes A and B. If the female is heterogametic and the male is homogametic, the what could be the chromosome arrangement of sex chromosomes in the adult?
A. Female AA and male BB
B. Female AB and male AB
C. Female AB and male BB
D. Female BB and male AB
27. What are pseudoautosomal regions on the sex chromosomes?
A. Homologous regions of the X and Y chromosomes
B. Hemizygous regions of the X and Y chromosomes
C. Homozygous region of the autosomal chromosomes
D. Regions of the X and Y chromosomes that don’t recombine during meiosis
28. Which of the following statements about Barr bodies is true?
A. They ensure that males and females have equal ‘doses’ of the genes on the
X chromosome
B. They are visible only in males
C. They contain no DNA
D. They are inactivated in Y chromosomes
29. A woman is color-blind. Her husband is not. If they have 3 children, then what is the probability that all of them will be color blind?
A. 1/8
B. 1/16
C. 1/4
D. 1/2
E. 1/6

26. Sex determination
A. Describe sex determination and how it is determined in humans
B. Describe TH Morgan’s experiment and findings from his sex linkage experiment in Drosophila
C. Give your own definition of a Barr body